DESCRIPTION: This Core serves the entire program by providing research design, data management, and biostatistical expertise to all investigators. Specifically, the Core will: provide consultation on design, sample size requirements, data collection instruments and data collection procedures for all studies; perform all data entry, accuracy checks, and quality control; ensure the security and integrity of all data files; perform primary and secondary statistical analyses for all projects as well as interim analyses for the Data Safety and Monitoring Board; facilitate the accurate and timely dissemination of research results.